Method for preparing a fluid absorber

ABSTRACT

Disclosed are a fluid absorber, a method for preparing a fluid absorber, and a method for absorbing fluid from the skin. The disclosed method for preparing a fluid absorber generally comprises the steps of selecting a starch and an enzyme for hydrolysis of the starch, determining a fluid absorption optimum hydrolysis level for the starch, and ezymatically hydrolyzing the starch to approximately the optimum level thus determined. The starch alternatively may be hydrolyzed with acid hydrolysis without the use of an enzyme catalyst. The disclosed method for absorbing fluid from the skin includes the step of applying a fluid absorbing effective amount of a fluid absorber thus prepared. Absorption properties of the fluid absorber of the invention are comparable to or exceed those of commercially available skin fluid absorbers, such as talc and unmodified corn starch.

RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.09/971,239, filed Oct. 04, 2001, now U.S. Pat. No. 6,946,148, whichclaims benefit of prior provisional U.S. application No. 60/237,918,filed Oct. 04, 2000.

TECHNICAL FIELD OF THE INVENTION

The invention relates to a method for absorbing fluid from the skin, andtowards a method for preparing a fluid absorber that is suitable forabsorbing fluid from the skin. The invention further provides a fluidabsorber which functions as a carrier for other products, in particularoleogenous products such as certain flavorings, and provides a methodfor absorbing such fluid, and a product carried by such a fluidabsorber. The fluid absorber used in conjunction with the inventioncomprises granular starch that has been partially hydrolyzed, preferablyvia enzymatic hydrolysis.

BACKGROUND OF THE INVENTION

Enzymes capable of hydrolyzing granular starch at temperatures below thestarch gelatinization temperature are known in the art. For instance, ithas long been known that alpha-amylases can hydrolyze granular starch,as disclosed in, for instance, Richert et al., Publication of theCarnegie Institution at Washington, No. 173, Part 1 (1913). Morerecently, other enzymes, such as glucoamylase enzymes, have also beenfound to hydrolyze granular starch below the starch gelatizationtemperature. It is believed that the presence of a starch-binding domainis essential for an enzyme to hydrolyze granular starch; numerousenzymes having such domains are known, as disclosed, for instance, inWalker, G. J. et al. Biochemical Journal, 86:452 (1963); Belshaw, N.J.et al., Biochim. Biophys. Acta, 1078:1117-20 (1991), and Svensson, B. etal., Eur. J. Biochem., 154:497-502 (1986). As is well known in the art,the term “enzyme hydrolysis” refers to enzyme-catalyzed hydrolysis, andthus enzymes such as alpha-amylase can be regarded as “hydrolyzing”starch via a catalytic hydrolytic action.

As is also known in the art, when a granular starch is treated with analpha amylase or a glucoamylase, the granular structure of the starchdegrades, leaving behind a porous starch granule upon partial hydrolysisof the starch, or, if the enzymatic hydrolysis is allowed to continue,yielding a starch hydrolyzate or ultimately glucose or another lowerorder sugar. It is also recognized that the enzymatic attack on starchgranules takes place by exo-corrosion in which the enzyme either erodesthe entire surface of the granule or digests a channel from points onthe surface towards the center of the granule. In the latter mode ofattack, once the center is reached, the enzymatic attack proceedsoutwardly from the center over a broader front. The internal structureof a porous starch granule that has been so modified is open andcavernous and can exhibit either a terraced or a step-shaped appearance.

When a glucoamylase enzyme is allowed to completely hydrolyze a starchgranule, the resulting product typically is glucose. U.S. Pat. Nos.2,583,451; 3,922,198; 3,922,199; 4,612,284; and 4;618,579 discloseprocesses for converting granular starch to glucose by treating of thestarch with glucoamylase or a mixture of glucoamylase withalpha-amylase. Other reaction products are possible; for instance, U.S.Pat. No. 3,922,201 discloses a process for the preparation oflevulose-containing compositions from granular starch by treating thestarch with alpha-amylase, glucoamylase, and glucose isomerase.

The prior art also has described the enzymatic hydrolysis of starchbelow the gelatinization temperature to produce starch hydrolyzes otherthan glucose. For instance, U.S. Pat. No. 3,922,196 discloses a processfor converting granular starch to a starch hydrolyzate having a DE(dextrose equivalent) between 40 and 55 and including a high percentageof disaccharides and trisaccharides. The process disclosed in thispatent employs alpha-amylase, glucoamylase, beta-amylase and isoamylase.Another document, U.S. Pat. No. 4,113,509, discloses an enzymaticallyproduced high maltose-maltotriose starch hydrolyzate having a DE of 40to 55. This patent discloses a process in which alpha-amylase, alone orwith a saccharifying enzyme such as glucoamylase or beta-amylase, isused to hydrolyze the starch. Methods for the production of othermalto-oligosaccharides such as maltose and maltotetraose by treatment ofstarch with specific alpha-amylases have also been employed on anindustrial scale.

The prior art also has provided applications for porous starches thatare obtained by partial enzymatic digestion of the granular starch. Forinstance, U.S. Pat. No. 4,985,082 discloses a starch matrix materialcomprising granular starch that is partially hydrolyzed with analpha-amylase and/or a glucoamylase and treated chemically to modify thestructural integrity and surface characteristics of the starch. Thedisclosed starches are said to be useful as adjuvants forantiperspirants and as bulking agents for foods and drinks. U.S. Pat.No. 4,551,177 discloses a compressible starch said to be useful as abinder for a tablet or capsule and which is said to be prepared bytreating granular starch with an acid and/or with an alpha-amylaseenzyme at a temperature below the gelatinization temperature of thestarch. Yet another document, U.S. Pat. No. 5,445,950, discloses amethod of using alpha amylase to prepare slightly decomposed starchgranules having low viscosity. The starch granules are said to be usefulas a raw material in the starch and sugar industry. U.S. Pat. No.5,904,941 discloses a viscosifier that comprises an enzymaticallyhydrolyzed, ungelatinized granular starch with a dextrose equivalent offrom about 5 to 60. Still another document, U.S. Pat. No. 5,935,826,discloses a modified starch prepared by the glucoamylase hydrolysis of astarch derivative that contains a hydrophobic group or both ahydrophobic and a hydrophilic group. The starches are said to becharacterized by having a DE from 20 to 80, and are said to be useful asemulsifiers or an encapsulating agents. International Patent PublicationWO 96/10586 discloses a method for preparing a fat substitute based onhydrolyzed granular starch. U.S. Pat. No. 5,919,486 discloses a powderpreparation that comprises a porous starch grain carrier and a materialcarried within the pores of the carrier, the porous starch grain carrierhaving been prepared by partially hydrolyzing starch with raw starchdigestive enzyme.

Other starches also have been used in dusting powder applications formany years, primarily to absorb more fluids from the skin. For example,U.S. Pat. No. 4,568,539 discloses compositions said to exhibit excellentmoisture absorbency and comprising starch and a specific pregelatinizedstarch. Another document, EP 182,296, discloses a body dusting powderthat comprises a porous starch granule which consists essentially of theresidue remaining after about from 45% to 95% by weight of the granularstarch has been solublized with an enzyme.

Skin fluids found on the skin surface typically comprise a complexmixture of sebum, lipids, sweat, and environmental or applied material.Because such fluids can provide nutrients and a moisture-richenvironment for microorganism to proliferate, such fluids can cause bodyodors and even in some cases bacterial and fungal infections. Theseeffects can be mitigated by applying a fluid-absorbing effective amountof a powdered starch composition as described in the prior art, or otherknown absorbents such as talc, cellulose derivatives, and so forth. Theaforementioned starch-based compositions are said to control excessmoisture, (i.e. the aqueous component of skin fluid), but are not saidto control the oily secretions produced by sebaceous glands.

It is a general object of the invention to provide a method forpreparing a fluid absorber that is effective in absorbing oil from theskin, and, more generally, that is effective in absorbing fluid from theskin. In other embodiments it is a general object to provide a fluidabsorber.

THE INVENTION

It has now been discovered that in many cases the oil absorbency of aporous starch product will be maximized at a starch hydrolysis levelthat is less in the hydrolysis level at which water absorption ismaximized. The invention makes use of this discovery by providing amethod in which the hydrolysis level of the starch is controlled tooptimize the fluid absorbency properties of the porous starch granulesfor use in absorbing fluid from the skin. It has further been found thatoil absorption of a porous starch granule will reach a plateau afterhydrolysis has proceeded to a certain extent, typically from about 30%to about 60%. The invention makes use of this discovery in certainembodiments to provide an essential fluid absorber not only for use inabsorbing fluids from the skin, but also for use in numerous otherapplications, such as a carrier. The term “fluid absorber” thus may bedeemed to include without limitation a product that in intended useabsorbs fluid (such as from the skin) or a product that carries anotherproduct, i.e. a carrier.

In accordance with a preferred embodiment of the invention, a method isprovided for preparing a fluid absorber. Generally, a granular starchand an enzyme for hydrolysis of the starch are selected, and, based onthe starch and enzyme chosen, a fluid absorption optimum hydrolysislevel is estimated. The starch then is enzymatically hydrolyzed underreaction conditions suitable to result in a porous granular starch, andthe enzymatic hydrolysis is terminated when the hydrolysis has proceededthrough a point within a predetermined range, typically within ±15%, orless, of the estimated fluid absorption optimum hydrolysis level. Inother general embodiments, the starch is hydrolyzed without the use ofan enzyme catalyst. In some embodiments, two hydrolyses are performed;one an acid hydrolysis that is not catalyzed enzymatically and one thatis catalyzed enzymatically. These hydrolyses may be performedsequentially, in either order. In accordance with another embodiment ofthe invention, a method for absorbing fluid from the skin is provided.The method comprises applying a fluid-absorbing effective amount ofporous starch granules prepared as described above. The fluid absorptionoptimum hydrolysis level may in some embodiments be considered to bethat in which the oil absorption is maximized. In other embodiments ofthe invention, the fluid absorption optimum hydrolysis level may bebased on the cumulative absorbence of the porous starch granule forvarious fluids, such as fluids that approximate the fluids found on theskin. One such fluid is a fluid that is composed of a mixture of water,1% saline (NaCl), and oil. The invention further encompasses a fluidabsorber prepared in accordance with the present teachings. Otherfeatures and embodiments of the invention are set forth hereinbelow.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph illustrating the data set forth in Example 1.

FIG. 2 is a graph illustrating the data set forth in Example 4.

DESCRIPTION OF PREFERRED EMBODIMENTS

Generally, the invention contemplates the partial hydrolysis of agranular starch, preferably with an enzyme. The starches that may beused as starting materials in preparing the porous starch granules maybe derived from any native source, and typical starch sources includecereals, tubers, roots, legumes, and fruits. Exemplary starches includethose obtained from corn, potato, wheat, rice, sago, tapioca, andsorghum. Corn starch is preferred in light of its low cost and readyavailability, and also in light of the known skin affinity of cornstarch and relative ease of modification of the granular structure ofcorn starch compared to starches such as potato. Suitable starchesinclude pearl starches, such as PURE-DENT® B700 and corn starch B200,both sold by Grain Processing Corporation of Muscatine, Iowa. Thestarches used in conjunction with the invention not only may be nativestarches but also may be starches that have been modified prior toenzymatic hydrolysis. Exemplary of such modified starches arecrossed-linked starches, which may comprise a native starch that havebeen crossed-linked via any suitable cross-linking technique known inthe art or otherwise found to be suitable in conjunction with theinvention. An example of a commercially available cross-linked starch isPURE-DENT® B850, sold by Grain Processing Corporation of Muscatine,Iowa. Other starches are deemed suitable for use in conjunction with theinvention, and thus, it is contemplated that, for instance, derivatized,or acid-thinned starches, or starches that have otherwise modified maybe employed. Exemplary starches include PURE-SET® B950, PURE-SET® B990,PURE-COAT® B70, SUPERBOND® B300, SUPERCORE® S22, COATMASTER® K56F andstarch C-165, all available from Grain Processing Corporation,Muscatine, Iowa.

In accordance with the invention, the starch is partially hydrolyzed,preferably with an enzyme. Suitable enzymes for using in conjunctionwith the invention include any of the wide variety of art-recognizedenzymes suitable for hydrolyzing starch, and include, for instance,amylases derived from fungal, bacterial, higher plant, or animal origin.Preferred examples of suitable enzymes include endo-alpha-amylases,which cleave the 1-4 glucoside linkage of starch. In addition, theenzyme may include or comprise a beta-amylase, which removesmaltose-units in a stepwise fashion from the non-reducing ends of thealpha 1-4 linkages; a glucoamylase, which remove glucose units in astepwise manner from the non-reducing end of starch and which cleavesboth 1-4 and the 1-6 linkages; and debranching enzymes such asisoamylase and pullulanase which cleave the 1-6 glucosidic linkages ofthe starch. Such enzymes can be used alone or in combination. Moregenerally, any starch that hydrolyses granular starch via the porousstarch granules may be employed in conjunction with the invention.

Preferred sources of alpha-amylases and pullulanases include severalspecies of the Bacillus micro-organism, such as Bacillus subtilis,Bacillus licheniformis, Bacillus coagulans, Bacillus amyloliquefaciens,Bacillus stearothermophilus, and Bacillus acidopullulyticlus, preferablythe thermal stable amylases produced by Bacillus stearothermophilus,Bacillus licheniformis, and Bacillus acidopullulyticus. Maltogenicalpha-amylase, an enzyme that produces high quantities of maltose andlow molecular weight saccaharides, is produced in Bacillus species; thisenzyme can be obtained from Novo Nordisk under the trademarkMALTOGENASE™. Preferred glucoamylases include those obtained fromstrains from Aspergillus niger. One alpha-amylase suitable inconjunction with the invention is G995, an alpha-amylase enzyme that iscommercially available from Enzyme Biosystems LTD. One glucoamylase thatis suitable for use in conjunction with the invention is G990, sold byEnzyme Biosystems Ltd.

The starch should be partially hydrolyzed with the selected enzyme toyield a porous starch granule. Generally, the enzymatic hydrolysis isaccomplished in an aqueous or buffered slurry at any suitable starchsolids level, preferably a solids level ranging from about 10% to about55% by weight on dry starch basis, more preferably about 25% to about35% by weight. The pH and temperature of the slurry should be adjustedto any conditions effective to allow enzyme hydrolysis. These will varydepending on the enzyme and starch selected, and are not critical solong as the starch does not gelatinize; generally, this can beaccomplished so long as the temperature remains below the gelatinizationtemperature of the starch. In general, the pH will range from about 3.5to about 7.5, more preferably from about 4.0 to about 6.0. To reach thispH, any suitable acid or base may be added, or a buffer may be employed.The temperature preferably is maintained at least 3° C. below thegelatinization temperature of the starch. For corn starch, thegelatinization temperature falls within a range between about 62° and72° C. Accordingly, the temperature of the slurry should be below about62° C., preferably ranging from about 22° C. to about 59° C., and morepreferably from about 51° C. to about 61° C.

The enzyme may be employed in any amount suitable to effectuate apartial hydrolysis of the starch granules in the slurry. Preferably, theenzyme is employed in the slurry in a concentration ranging from about0.2% to about 3% by weight on dry starch, and more preferably from about0.4% to about 2%. For glucoamylase, this range is based on a 300 unitper ml enzyme (based on the Enzyme Biosystems unit definition); foralpha-amylase, this range is based on a 2200-5000 unit/ml enzyme For themaltogenic alpha-amylase, the units are based on a commercial 4000unit/ml enzyme (MALTOGENASE from Novo Nordisk).

When it is desired to terminate the enzymatic hydrolysis, the enzymatichydrolysis may be terminated by any suitable techniques known in theart, including acid or base deactivation, ion exchange, solventextraction, or other suitable techniques. Preferably, heat deactivationis not employed, since a granular starch product is desired and sincethe application of heat in an amount sufficient to terminate theenzymatic reaction may cause gelatinization of the starch. For typicalenzymes, acid deactivation may be accomplished by lowering the pH to avalue lower than 2.0 for at least 5 minutes, typically for 5 to 30minutes. After deactivation, the pH of the slurry may be readjusted tothe desired pH according to the intended end use of the granules.Typically, the pH will be adjusted to a pH within the range from about5.0 to 7.0, more preferably from about 5.0 to about 6.0. The starchgranules thus prepared then can be recovered using techniques known inthe art, including filtration and centrifugation. Preferably, thereducing sugars and other byproducts produced during the enzymatictreatment are removed during the washing steps. Most preferably, thestarch granules subsequently are dried to a moisture content of or belowabout 12%.

In other embodiments of the invention, the starch granules arehydrolyzed via acid hydrolysis without the use of an enzyme. In suchembodiments, the starch is placed in an aqueous acid medium at a low pH(typically a pH below 2.0, and more preferably below 1.0) at an elevatedtemperature for a time sufficient to hydrolyze the starch. Those skilledin the art will appreciate that many reaction conditions may beemployed. For instance, the hydrolysis time may range from a few hoursto a period of days. Generally, the starch solids level and temperatureshould be within the ranges described above with respect to enzymatichydrolysis. When it is desired to terminate the hydrolysis, the pHshould be adjusted to a level sufficient to terminate substantiallycompletely the hydrolysis (typically to a pH ranging from about 5-7).The starch is preferably dried, as discussed hereinabove. While thismethod is suitable for the hydrolysis of starch, use of an enzyme ispreferred, inasmuch as it is believed such use will provide a degree ofregional specificity of hydrolysis of the starch granule that will belacking absent the use of an enzyme. It is further believed that the useof an enzyme will affect the absorption properties of the resultingporous starch granules. Also, enzyme catalysts allow operation at moremoderate pH levels.

In some embodiments of the invention, two hydrolyses are performed; onean emzymatically catalyzed hydrolysis and one not catalyzedenzymatically. The hydrolyses may be performed in either order.Preferably, the first of the hydrolyses is terminated after the starchgranule has been hydrolyzed to an extent of about 50% of the desiredextent of hydrolysis and the second hydrolysis is next commenced andallowed to proceed to finish the hydrolysis to the desired extent. Moregenerally, the first hydrolysis may be allowed to proceed from about 10%to about 90% of the desired extent.

In accordance with a preferred embodiment of the invention, the starchis hydrolyzed to an optimum fluid absorption hydrolysis level. By“hydrolysis level” is contemplated the percentage of the starch granulethat is enzymatically hydrolyzed and thus no longer remaining ingranular form. The optimum fluid absorption hydrolysis level mostpreferably is determined empirically, that is, by testing the absorptionproperties for a specific starch hydrolyzed with the specific enzymebeing contemplated at various hydrolysis levels and estimating from thisinformation the hydrolysis level that yields the optimum fluidabsorption property. The hydrolysis level alternatively may bedetermined via reference to a predetermined correlation of fluidabsorption levels and hydrolysis levels. If the optimum hydrolysis levelis known in advance, the “determination” of the optimum hydrolysis levelmay be simply predetermining the hydrolysis level with reference orregard to the known optimum level. In any event, the extent ofhydrolysis of starch in a given hydrolysis reaction may be determined orestimated from the reaction time.

The optimum fluid absorption property may be defined in any mannerconsistent with the ultimate intended purpose of the starch, forinstance, in connection with the goal of absorbing fluids from the skin.For instance, in one embodiment of the invention, the optimum fluidabsorption may be defined as the maximum oil absorption, i.e., the fluidabsorption optimum hydrolysis level may be taken as the minimumhydrolysis level at which oil absorption is maximized (reaches anapparent plateau). Any suitable oil, such as a mineral oil, may be usedto approximate oils found in the surface of the skin. More generally,other fluids may be used to approximate the composition of fluids on theskin. For instance, the fluid on the surface of the skin may beestimated to comprise a combination of water, 1% saline (NaCl), and oil.The fluid absorption optimum hydrolysis level may be regarded as thathydrolysis level at which the absorption of oil water, 1% saline, andoil is deemed to be cumulatively optimized; this may be regarded as theminimum hydrolysis level at when the oil absorption reaches an apparentmaximum. Alternatively, weighting factors may be applied to the water,saline, and oil absorption parameters in order to further approximatethe composition of fluids from the skin. Such weighting factors may beempirically determined. If there is no one level which the fluidabsorption is maximized (for instance, if there is a range of hydrolysislevels at which fluid hydrolysis is constant), any point in such rangemay be regarded as the optimum level. Alternatively, the lowesthydrolysis level in such range may be regarded as optimum. In otherembodiments the optimum fluid hydrolysis level may be empiricallyestimated.

The enzymatic or acid hydrolysis should be allowed to continue to withina selected range surrounding the estimated fluid absorption optimumhydrolysis level. Any suitable range may be selected. For instance, oncethe fluid absorption optimum hydrolysis level has been estimated, thehydrolysis may be allowed to proceed to within ±15%, more preferably±10% and even more preferably ±5%, of the estimated optimum level. Forinstance, using corn starch, the optimum hydrolysis level in severalembodiments may range from about 30% to about 50%, in some embodiments,about 30% to about 44%; in other embodiments; from about 35% to about44%; in other embodiments from about 38% to about 42%; and in otherembodiments the hydrolysis level may be about 40%. This optimumrepresents the lowest hydrolysis level at which oil absorption reachesan apparent plateau.

Once the fluid absorption optimum hydrolysis level has been determined,the starch is hydrolyzed with the enzyme to within the selected rangesurrounding the optimum level. The granules can be recovered using anysuitable technique known in the art or otherwise found to be suitable,including filtration and centrifugation.

In preparing a fluid absorber for the skin, the starch granules thusprepared most preferably are ground to provide ground granules afterwashing and drying. In absorbing fluid from the skin, the groundgranules may be applied in any amount effective to absorb fluidtherefrom. The ground granules may be used alone, or in combination withother ingredients. In accordance with one embodiment of the invention,for instance, a fluid absorber includes the ground granules prepared inaccordance with the present technical and a fragrance. In otherembodiments, the granules are used as a carrier for materials such ascolorants, flavorants and other materials (in particular oleogenousmaterials).

Exemplary applications for the non-ground starches prepared inaccordance with the invention include plating agents for flavors andfragrances; plating agents for sticky or oily food products such aspeanut butter, honey, and molasses; plating of lecithin; plating ofcolors; flow aids on shredded cheeses; stabilizing agents for products(e.g. cream cheese, to keep oil from separating out); coating agents(e.g., for pepperoni slices to prevent sticking together); plating forfats, such as chicken fat; plating to prevent oil separation in sauces;flow aids in dry sauce mixes; absorbers for moisture in dry mixes;plating agents for pharmaceutically active materials (e.g. prior toencapsulation); plating of oleoresins; carriers for oils such as fishoil, and thickeners for materials such as oils (e.g. olive oil).Exemplary applications for the ground starches prepared in accordancewith the invention include fluid absorbing agents in body and “shower”powders; fluid absorbing agents in other personal care products such asdry hair care products, lip balms, antiperspirants and deodorants, footpowers, dispensing body powders, natural soaps, sun tan lotions, andbody lotions; plating agents for colors and flavors (for instance, as acarrier for colorants for facial powder); plating agents forpharmaceutically active materials; absorbents in medicated patches andplating agents for simethicone. This list is by no means exhaustive, butto the contrary it is contemplated that the starches prepared inaccordance with the invention will find use in numerous otherapplications. More generally, any starch that has been hydrolyzed viaenzymatic hydrolysis or otherwise to form a fluid absorber should bedeemed useful in connection with such applications. The invention shouldbe deemed to include the use of such porous starches in suchapplications. Preferably, but necessarily, the starch used in suchapplications is hydrolyzed to an estimated fluid absorption optimumhydrolysis level.

The following examples are provided to further illustrate the invention,but should not be construed as limiting the invention in scope.

EXAMPLES

The following procedure was used to estimate water, saline, and oilabsorption.

Prior to testing, each sample was screened through a 120 mesh (US)screen (0.0125 cm-0.0049 in.). In accordance with ASTM D281-95, to 10.0g (dry solid basis) starch (weighed in a 100 ml beaker) was addeddropwise water, 1% salt water, or a mineral oil (CHEVRON SUPERLA #7)until a stiff, putty-like paste was formed. The precision of this testis +/−0.5 ml and gives an indication of the saturation value of thestarch.

Example 1

This example shows how the degree of hydrolysis can affect the water,salt water, and oil absorption properties of starch granules.

In 1250 ml tap water was slurried 500 grams (dry solids basis) of dentcorn starch. The slurry was heated to a temperature of either 51° C. or60° C., as indicated in Table 1, and the pH was adjusted to theindicated value using dilute hydrochloric acid. The amount ofalpha-amylase (G995, commercially available from Enzyme Bio-SystemsLtd., and BAN and TERMAMYL 120 L, commercially available from NovoNordisk) indicated in Table 1 was added and the reaction was allowed toproceed at the indicated temperature with constant mixing for theindicated amount of time. The enzyme was then deactivated by reducingthe pH to 1.9 with dilute hydrochloric acid. After 5 minutes at pH 1.9,the pH of the slurry was adjusted to 5.0-5.5 with dilute sodiumhydroxide. The reaction mixture was filtered, washed with tap water, anddried. The hydrolysis conditions and absorption test results are shownin Table 1. “Yield” in these tables refers to yield of insoluble starchgranules.

TABLE 1 Absorption Conditions (ml/10 g basis) 1% Temp. pH Enzyme TimeYield Water Salt Oil — — None — — 8.0 9.0 7.0 51° C. 6.30 0.26 ml  8 h87.1% 9.5 10.0 9.5 BAN 51° C. 6.50 0.26 ml  8 h 84.9% 10.0 10.5 10.0TERMAMYL 51° C. 5.80 0.13 ml 24 h 75.5% 11.0 12.0 11.0 G995 60° C. 5.20 1.3 ml  8 h 58.8% 14.5 15.5 12.5 G995 51° C. 5.80 1.30 ml 48 h 55.0%15.5 16.5 13.0 G995 60° C. 5.80 13.0 ml  8 h 40.4% 16.5 17.0 12.0 G995

In this example, water and 1% salt water absorption of alpha-amylasetreated corn starches are similar and increase with increasinghydrolysis yield, while a limit surprisingly is observed with oilabsorption, this limit occurring at around 60% yield (40% hydrolysis).All alpha-amylase treated starches display higher water and oilabsorption than untreated corn starch. FIG. 1 shows that, for water and1% saline, the relationship between absorption and percent hydrolysis isessentially linear over a broad range, while the oil absorbance reachesa plateau.

Example 2

This example shows how the degree of hydrolysis can affect the water andoil absorption of starch granules that have been hydrolyzed with amaltogenic alpha-amylase, and how similar treatment with alpha-amylaseor a maltogenic alpha-amylase can lead to different absorptionproperties.

500 grams (dry solids basis) of dent corn starch were slurried in 1250ml tap water. The slurry was heated to 60° C. and the pH adjusted to5.15 using dilute hydrochloric acid. The amount of maltogenicalpha-amylase (MALTOGENASE 4000L, commercially available from NovoNordisk) indicated in Table 2 was added and the reaction was allowed toproceed at 60° C. with constant mixing for the indicated amount of time.The enzyme was then deactivated by reducing the pH to 1.9 with dilutehydrochloric acid. After 5 minutes at pH 1.9, the pH was adjusted to5.0-5.5 with dilute sodium hydroxide. The reaction mixture was filtered,washed with tap water and dried. The hydrolysis conditions andabsorption test results are shown in Table 2.

TABLE 2 Absorption Conditions (ml/10 g basis) Temp. pH Enzyme Time YieldWater 1% Salt Oil — — None — — 8.0 9.0 7.0 60° C. 5.15    2.0 ml    8 h85.7% 11.0 11.0 8.5 MALTO- GENASE 60° C. 5.15    5.0 ml    8 h 77.0%11.0 11.5 11.0 MALTO- GENASE 60° C. 5.15   10.0 ml   24 h 69.8% 13.512.5 11.0 MALTO- GENASE 60° C. 5.15   10.0 ml    8 h 54.7% 14.5 15.011.0 MALTO- GENASE  +5.0 ml  +5 h MALTO- GENASE

In the last experiment, the starch was treated with 10 ml MALTOGENASEfor 10 hours, and 5 ml MALTOGENASE were subsequently added and thereaction allowed to proceed for 5 hours. In this example, water and 1%salt water absorption of maltogenic alpha-amylase treated corn starchesare similar and increase with increasing hydrolysis yield, while a limitis observed with oil absorption, occurring at around 70% yield. Oilabsorption was lower for the of maltogenic alpha-amylase treatedstarches of the example than for the alpha-amylase treated starches ofexample 1. For a similar hydrolysis level, oil absorption ofalpha-amylase and of maltogenic alpha-amylase treated starches weredifferent.

Example 3

This example shows how the level of hydrolysis can affect the water andoil absorption of starch granules, and how similar treatment withdifferent enzymes can lead to different absorption properties.

500 grams (dry solids basis) of dent corn starch were slurried in 1250ml tap water. The slurry was heated to 60° C. and the pH adjusted to5.20 using dilute hydrochloric acid. The amounts of alpha-amylase andpullulanase (G995 and ULTRADEX, a pullulanase enzyme commerciallyavailable from Enzyme Bio-Systems Ltd., PROMOZYME, a pullulanase enzymecommercially available from Novo Nordisk) indicated in Table 3 wereadded and the reaction was allowed to proceed at 60° C. with constantmixing for the indicated amount of time. The enzymes were thendeactivated by reducing the pH to 1.9 with dilute hydrochloric acid.After 5 minutes at pH 1.9, the pH was adjusted to 5.0-5.5 with dilutesodium hydroxide. The reaction mixture was filtered, washed with tapwater and dried. The hydrolysis conditions and absorption test resultsare shown in Table 3.

TABLE 3 Absorption Conditions (ml/10 g basis) Enzyme Time Yield Water 1%Salt Oil None — — 8.0 9.0 7.0 0.65 ml G995 + 2 h 71.2% 12.5 12.5 10.52.6 ml PROMOZYME 1.3 ml G995 + 6 h 61.3% 14.0 15.0 12.5 1.3 ml ULTRADEX2.6 ml G995 + 6 h 56.1% 15.0 14.5 12.0 2.6 ml ULTRADEX 4.0 ml G995 + 8 h52.5% 16.0 16.0 11.5 4.0 ml ULTRADEX

The water, and 1% salt water absorption of alpha-amylase-pullulanasetreated corn starches of this example were similar to alpha-amylasetreated starches of example 1, while a lower oil absorption limit wasobserved, occurring at around 60% hydrolysis yield.

Example 4

This example demonstrates that the degree of hydrolysis can affect thewater and oil absorption of starch granules, and how similar treatmentwith different enzymes can lead to different absorption properties.

500 grams (dry solids basis) of dent corn starch were slurried in 1250ml tap water. The slurry was heated to 60° C. and the pH adjusted to5.20 using dilute hydrochloric acid. The amounts of glucoamylase andalpha-amylase (G990 and G995, commercially available from EnzymeBio-Systems Ltd.) indicated in Table 4 were added and the reaction wasallowed to proceed at 60° C. with constant mixing for the indicatedamount of time. The enzymes were then deactivated by reducing the pH to1.9 with dilute hydrochloric acid. After 5 minutes at pH 1.9, the pH wasadjusted to 5.0-5.5 with dilute sodium hydroxide. The reaction mixturewas filtered, washed with tap water and dried. The conditions andabsorption test results are shown in Table 4.

TABLE 4 Absorption Conditions (ml/10 g basis) Enzyme Time Yield Water 1%Salt Oil None — — 8.0 9.0 7.0  5.0 ml G990 2 h 91.8% 11.5 11.0 8.5  5.0ml G990 4 h 90.5% 12.0 11.5 8.5 10.0 ml G990 2 h 89.7% 12.5 12.5 8.5 5.0 ml G990 6 h 87.5% 12.5 12.5 9.0 10.0 ml G990 6 h 70.4% 14.0 14.09.0 0.05 ml G995 + 5.0 ml G990 8 h 68.5% 15.0 15.5 11.0 0.65 ml G995 +5.0 ml G990 2 h 50.9% 16.5 16.5 11.5  1.3 ml G995 + 10.0 ml G990 2 h39.2% 16.0 17.0 10.0  1.3 ml G995 + 10.0 ml G990 4 h 28.3% 17.5 17.510.5  1.3 ml G995 + 10.0 ml G990 6 h 25.0% 17.5 17.5 11.0  1.3 ml G995 +10.0 ml G990 8 h 21.0% 18.5 18.0 10.5

FIG. 2 illustrates that the oil absorbance reaches a plateau at about60% yield (40% hydrolysis), while absorbance of water and salineincreases in an approximately linear manner.

Example 5

This example shows how the starch type can affect the water and oilabsorption of starch granules, as indicated by hydrolysis level.

In separate experiments, 500 grams (dry solid basis) of B850, a highlycross-linked corn starch sold by Grain Processing Corporation ofMuscatine, Iowa, and VINAMYL II, a high amylose starch sold by NationalStarch, & Chemical Company, were slurried in 1250 ml tap water. Eachslurry was heated to 60° C. and the pH adjusted to 5.7 using dilutehydrochloric acid. The amounts of alpha-amylase (G995, commerciallyavailable from Enzyme Bio-Systems, Ltd.) indicated in Table 5 were addedand the reaction was allowed to proceed at 60° C. with constant mixingfor 8 h. The enzymes were then deactivated by reducing the pH to 1.9with dilute hydrochloric acid. After 5 minutes at pH 1.9, the pH wasadjusted to 5.0-5.5 with dilute sodium hydroxide. The reaction mixturewas filtered, washed with tap water and dried. The hydrolysis conditionsand absorption test results are shown in Table 5.

TABLE 5 Absorption G995 % (ml/10 g basis) Starch Type Dosage HydrolysisWater 1% Salt Water Oil Corn — — 8.0 9.0 7.0 Corn 1.3 ml 41.2 14.5 15.512.5 B850 — — 8.5 9.0 7.0 B850 1.3 35.9 13.5 14.5 11.0 B850 2.6 43.616.0 15.5 11.5 High Amylose — — 11.0 11.0 10.5 High Amylose 1.3 34.917.5 15.5 9.0

These results show that highly cross-linked corn starch and high amylosestarch are not as susceptible to G995 hydrolysis than active cornstarch, and that water and oil absorption can differ, for the samehydrolysis level, with the starch type. Water absorption in this examplewas the highest for high amylose starch while oil absorption was lowerfor this starch.

Example 6

This example shows how the alpha-amylase treated corn starch outperformscommercial baby powders for water, 1% salt water, and oil absorption.

TABLE 6 Absorption (ml/10 g basis) Fluid Absorber Water 1% Salt WaterOil Commercial Talc 7.0 8.0 8.5 Commercial Talc 8.0 9.0 10.5 Commercialcorn starch baby power 10.0 9.5 7.5 Alpha-amylase treated corn starch14.5 15.5 12.5

As seen, the starch of the present invention outperformed the commercialbaby powders for water, 1% salt water, and oil absorption.

Example 7

This example demonstrates how the characteristics of granular starch canbe affected by enzymatic treatment.

TABLE 7 Loose Bulk Enzyme Density Surface/Area Starch Treatment %Hydrolysis (g/cm³) (m²/g) Corn — — 0.62 0.32 Corn α-Amylase G995 28.70.52 1.09 Corn α-Amylase G995 41.2 0.46 1.14 Corn G995/G990 75.0 0.491.34As seen, the enzymatic treatment increases the surface area whilelowering the density of the granules.

Example 8

This example illustrates the preparation of a fluid absorber via acidhydrolysis of starch.

Starch, (B200, 643.5 g dry solids basis) was added to 1250 mL of waterto make a 34% solids slurry. The mixture was heated to 59° C. The pH wasadjusted to below 1 by the addition of a total of 50 mL of 1:1concentrated hydrochloric acid:water. After 24 hours at 59° C., thereaction was cooled and pH adjusted to 5.3 with soda ash. The resultingmixture was filtered, washed 2×400 mL with water and dried overnight at50° C.

Example 9

This example illustrates the preparation of another fluid absorber.

A fluid absorber was produced according to the procedure described inSample 8, except that 55 mL of 1:1 concentrated hydrochloric acid:waterwas used instead of 50 mL.

Example 10

This example illustrates the preparation of a fluid absorber via acidhydrolysis of starch followed by enzymatic hydrolysis.

Starch, (B200, 562 g dry solids basis) was added to 1250 mL of water tomake a 40% solids slurry. The mixture was heated to 60° C. The pH wasadjusted to below 1 by the addition of a total of 30 mL of 1:1concentrated hydrochloric acid:water. After 17 hours at 60° C., thereaction was cooled and pH adjusted to 5.8 with soda ash. Enzyme (G995α-amylase, 1.3 mL) was added to the mixture and it was stirred anadditional 4 hours. The slurry was then cooled to room temperature. ThepH of the reaction was then adjusted to 1.9 with 1:1 concentratedhydrochloric acid:water and held at this pH for five minutes toterminate all enzyme activity. The pH was then re-adjusted to 5.4 with3% NaOH, and filtered, washed and dried as in Example 8.

Example 11

This example illustrates the preparation of another fluid absorber viaacid hydrolysis of starch, followed by enzymatic hydrolysis.

Acid thinned starch (B950, 500 g dry solids) was added to 1250 mL ofwater to make a 28% solids starch slurry. The mixture was heated to 60°C. The pH was adjusted to 5.8 with 3% NaOH. Enzyme (G995 α-amylase, 1.3mL) was added to the mixture and it was stirred for 4 hours. The slurrywas then cooled to room temperature. The pH of the reaction was thenadjusted to 1.9 with 1:1 concentrated hydrochloric acid:water and heldat this pH for five minutes to terminate all enzyme activity. The pH wasthen re-adjusted to 5.4 with 3% NaOH, and filtered, washed and dried asin Example 8.

Example 12

This example illustrates the preparation of a fluid absorber byenzymatic hydrolysis of starch, followed by acid hydrolysis.

Starch, (B200, 500 g dry solids basis) was added to 1250 mL of water tomake a 28% solids slurry. The mixture was heated to 60° C. The pH wasadjusted to 5.8 with 3% NaOH. Enzyme (G995 α-amylase, 1.3 mL) was addedto the mixture and it was stirred for 4 hours. The pH of the reactionwas then dropped to below 1 by the addition of 50 mL of 1:1 concentratedhydrochloric acid:water. After 4 hours at 60° C., the reaction wascooled and pH adjusted to 5.8 with soda ash. The slurry was thenfiltered, washed and dried as in Example 8.

Example 13

This example illustrates the preparation of a second fluid absorber byenzymatic hydrolysis of starch followed by acid hydrolysis.

A fluid absorber was produced according to the procedure described inExample 12, except that 30 mL of 1:1 concentrated hydrochloricacid:water was used instead of 50 mL.

Example 14

Starch (B200, 500 g dry solids basis) was added to 1250 mL of water tomake a 28% solids slurry. The mixture was heated to 60° C. The pH wasadjusted to 5.8 with 1:1 concentrated hydrochloric acid:water. Enzyme(G995 α-amylase, 1.3 mL) was added to the mixture and it was stirred for8 hours. The pH of the reaction was then adjusted to 1.8 with 1:1concentrated hydrochloric acid:water and held at this pH for fiveminutes to kill enzyme activity. The pH was then re-adjusted to 5.3 with3% NaOH. The mixture then was filtered, washed (2×400 mL) and dried. Theresulting product had a oil absorbency of 12.0 mL per 10 g of starch anda water absorbency of 15.5 mL per 10 g of starch.

The following table summarizes absorption data for hydrolyzed granularstarches made via enzyme, acid or combined enzyme/acid proceduresoutlined in examples 5 and 8 through 14.

Absorption (mL/10 g) Sample Treatment % Yield Water Oil B200 None — 8.57.5 Example 5 Enzyme 59 14.5 12.5 (entry 2 in Table 5) Example 8 Acid 7015 7.5 Example 9 Acid 70 12.8 9.0 Example 10 Acid, then 52 19.8 8.0enzyme Example 11 Acid, then 66 12.8 9.0 enzyme Example 12 Enzyme, then60 12.4 9.5 acid Example 13 Enzyme, then 60 12.4 10.5 acid Example 14Enzyme 54 15.5 12.0The data shows that acid hydrolysis and/or acid/enzyme hydrolysis doimprove water and oil absorption when compared to untreated starch. Acidand enzyme sequential hydrolyses do not show any improvements overenzyme catalyzed acid hydrolysis, especially in the ability to absorbwater and oil in relatively equal amounts. Acid hydrolysis, followed byenzyme hydrolysis may be a way to allow the enzyme more access to thegranule, which could lead to some unique properties, as demonstrated bythe high water absorption in Example 10. However, oil absorption of thissample was relatively low.

Example 15

This example illustrates the hydrolysis of starch to prepare a fluidabsorber.

Based on the preceeding examples, it was determined that, for dent cornstarch, the optimum hydrolysis level is about 40% (“optimum” beingdefined as the minimum hydrolysis level at which the oil absorptionreaches an apparent plateau).

Dent corn starch slurry was diluted to 28% solids (Baume 15.8@ 60° F.).The total volume of the mixture was 380 gallons (1000 lbs). The pH ofthe mixture was adjusted to 5.6 by the addition of 250 mL ofconcentrated hydrochloric acid. The reaction temperature was adjusted to136-140° F. and 1000 mL of G995 alpha amylase enzyme (Enzyme Biosystems)was added to the mixture. The reaction was stirred at temperature for 4hours and then another 100 mL of G995 was added. The reaction wasstirred for eight more hours. The pH of the reaction throughout thetwelve-hour reaction time was held at 5.4-5.8. The reaction was thenquenched by the addition of 2.0 L of concentrated HCL. The pH afterquench was 1.9. The starch slurry was held at pH 1.9 for 15 minutes andthen neutralized with 25.8 L of 3% NaOH to a pH of 5.3. The mixture wasthen filtered, washed and dried. The oil absorbance of 10 g of materialwas 13.0 mL.

Example 16

This example illustrates the preparation of a bleached product.

Dent corn starch was diluted to 28% solids (Baume 15.8@ 60° F.). Thetotal volume was the mixture was 38 gallons (100 lbs). The pH of themixture was adjusted to 5.6 by the addition of 18 mL of concentratedhydrochloric acid. The reaction temperature was adjusted to 136-140° F.and 100 mL of G995 alpha amylase enzyme (Enzyme Biosystems) was added tothe mixture. The reaction was stirred at temperature for 4 hours andthen another 100 mL of G995 was added. The reaction was stirred foreight more hours. The pH of the reaction throughout the twelve-hourreaction time was held at 5.4-5.8. The reaction was then quenched by theaddition of 0.34 gallons of sodium hypochlorite (0.5%, 17.65% activechlorine). The hypochlorite addition was over a 20 minute period, andthe final pH of the reaction was 8.2. One hour after the hypochloriteaddition, sodium bisulfite, 100 grams, was added and the mixture wasstirred for an additional fifteen minutes to ensure no residual oxidantremained. The pH of the mixture was then adjusted to 5.4, filtered andwashed. The resulting product was dried and ground. The screen size ofthe ground product was 99.9% through a 100 mesh and 78% through a 325mesh screen. The Minolta color of the sample was L=97.00, b=2.37. Thewater and oil absorbance of 10 g of material was 14.0 mL and 12.0 mL,respectively.

Example 17

The fluid absorber prepared in accordance with Example 15 is blendedwith a fragrance. The product thus prepared is used to absorb oil fromthe skin.

Example 18

The fluid absorber used in accordance with Example 15 is used to absorban oleogenous flavoring agent. The product thus prepared is added to afood product to provide flavor.

It is thus seen that the invention provides a method for absorbing fluidfrom the skin, and also a method for preparing a fluid absorber.

While particular embodiments of the invention have been shown, it willbe understood that the invention is not limited thereto sincemodifications may be made by those skilled in the art, particularly inlight of the foregoing teachings. For instance, the invention isoperable to absorb fluids not only from human skin but also from animalskin. It is, therefore, contemplated by the appended claims to cover anysuch modifications as incorporate those features which constitute theessential features of these improvements within the true spirit andscope of the invention. All references cited herein are herebyincorporated by reference in their entireties.

1. A method for preparing a fluid absorber, comprising: providing agranular starch; determining an estimated oil absorption maximumhydrolysis level for said starch; partially enzymatically hydrolyzingsaid starch under hydrolysis conditions suitable to provide a porousstarch granule; and terminating said enzymatic hydrolysis when saidstarch has been hydrolyzed to an optimum oil absorption hydrolysis levelranging from about 30% to about 42%.
 2. A method according to claim 1,said starch enzyme being selected from the group consisting ofglucoamylase enzymes, alpha-amylase enzymes, maltogenic alpha-amylaseenzymes, isoamylase enzymes, and pullulanase enzymes.
 3. A methodaccording to claim 1, said hydrolysis level ranging from about 35 toabout 42%.
 4. A method according to claim 1, said hydrolysis levelranging from about 38% to about 42%.
 5. A method according to claim 1,said hydrolysis level being about 40%.
 6. A method according to claim 1,including grinding said porous starch granules to form ground granules.7. A method according to claim 1, said starch comprising corn starch. 8.A method according to claim 1, including adding a fragrance.